Session: 35-03 Compressors & ducts integration

Submission Number: 175840

The Impact of a Chevron Outlet Geometry of Pulsed Jet Actuators in a Highly Aggressive Inter Compressor Duct 

Highly aggressive Inter Compressor Duct (ICD) are a suitable mean to reduce the total length and weight of the jet engine. The resulting challenge of flow separation within the flow path, caused by the strong flow deflection in the steeply curved duct towards the lower radius, needs to be addressed. Within this study, an Active Flow Control system (AFC) equipped with Pulsed Jet Actuators (PJA) featuring Chevrons is implemented in the ICD domain.

Most promising positioning and blowing configuration of the AFC with respect to minimize losses were determined by numerical optimization using AutoOpti. The experimental validation of the optimized PJAs is carried out at the ICD test rig at TU Berlin. Furthermore, the experimental data serves as a benchmark for the numerical simulations.

After the initial tests with the optimized PJA outlet positions, the implementation of a chevron geometry in the PJA outlet is introduced. Intention was the increase of mixing area for the main flow and the jet emanating from the PJA to further decrease the flow losses within the ICD. For the experimental investigation two different chevron designs were selected and tested for different outlet positions in the ICD passage.

The chevron outlet geometry is implemented in two different forms. The first is the chevron with 8 teeth on each side. The second version is equipped with 16 teeth on each side and rounded edges on the inside of the teeth.

Directly behind the ICD Domain, five-hole probe measurements are conducted to analyse the influence of the active flow control system. The resulting wake flow fields span one passage with the strut in the middle. The normalized stagnation pressure is used to analyse the results.

The implementation of chevron outlet orifices seems to have not the beneficial effect on the tip side losses of the ICD compared to the initial rectangular outlet orifices.

Particle Image Velocimetry (PIV) measurements have been conducted, to even better understand the mixing of the jet and the main flow influenced by the different chevron geometry configurations. In parallel numerical investigations of the chevron outlets are done to gain an in-depth understanding of the ICD flow topology.

The results indicate that the chevron outlets are not well suited to reduce the losses in the ICD.

Presenting Author: David Bresemann Technical University Berlin

Presenting Author Biography: David Bresemann is a research assistant with the Institute of Aeronautics and Astronautics of the Technical University Berlin since 2021. After his initial experimental research on tandem rotor blades he changed his research focus to the experimental investigation of active flow control in the inter compressor duct. Furthermore, he worked since 2017 as a student assistant on the tandem blade project. Before his academic education he had done an apprenticeship as an aircraft engine mechanic.

Authors:

David Bresemann Technical University Berlin
Mario Eck Technische Universität Berlin
Dieter Peitsch Technische Universität Berlin
Stefan Fritz German Aerospace Center (DLR)
Alexander Hergt German Aerospace Center (DLR)
Ben Steinfurth Technische Universität Berlin